Interleukin 2-activated human killer cells are derived from phenotypically heterogeneous precursors

Area of Science:

• Immunology
• Cell Biology

Background:

• Interleukin 2 (IL 2) is a cytokine crucial for immune responses.
• IL 2-activated killer (IAK) cells, also known as LAK cells, exhibit potent anti-tumor activity.
• Understanding the cellular origins of IAK cells is vital for immunotherapy development.

Purpose of the Study:

• To investigate which human peripheral blood mononuclear cell (NAMNC) subpopulations can generate IAK activity upon IL 2 stimulation.
• To define the surface phenotype of precursors responsible for IAK cell generation.

Main Methods:

• Human NAMNC were isolated and separated into subpopulations based on surface markers using monoclonal antibodies.
• Subpopulations were cultured with IL 2 and assessed for their ability to lyse tumor target cells.
• Flow cytometry and functional assays were employed to characterize cell populations and their cytotoxic potential.

Main Results:

• Both CD16+ NK cells and CD16- non-T cells generated IAK activity.
• CD2+ T cells and CD2- non-T cells were capable of differentiating into IAK cells.
• Both CD4+ and CD8+ T cell subsets, as well as CD20+ B cells, could develop into IAK cells.
• Specific T cell subsets (CD4+Leu-8+, CD4+Leu-8-, CD8+9.3+, CD8+9.3-) were identified as precursors for IAK cells.

Conclusions:

• IAK cell activity is not restricted to a single cell type but originates from phenotypically diverse human lymphoid cells.
• Both T and non-T cell populations, including B cells and various T cell subsets, can differentiate into IAK cells.
• The findings highlight the broad potential of human peripheral blood cells to generate cytotoxic effector cells upon IL 2 activation.